1. Field of the Invention
The present invention relates to a semiconductor device.
2. Description of Related Art
A semiconductor device according to a prior art is disclosed, for example, in Patent Document 1 (Japanese Published Unexamined Patent Application No. Hei 10-341018).
The semiconductor device disclosed in FIG. 1 of Patent Document 1 includes a thick-film SOI (silicon on insulator) substrate. The thick-film SOI substrate has a structure where an n−-type semiconductor layer is laminated on a semiconductor substrate (silicon substrate) via an embedded insulation layer. A diode is formed in the n−-type semiconductor layer.
The diode has an n+ semiconductor region and a p+ semiconductor region. A region of the n−-type semiconductor layer is used as an n− drift region that forms a pn junction with the p+ semiconductor region.
A cathode electrode is formed so as to be electrically connected to the n+ semiconductor region. Also, an anode electrode is formed so as to be electrically connected to the p+ semiconductor region.
An insulation layer provided on the n− semiconductor layer electrically isolates the cathode electrode and the anode electrode from other portions.
Also, capacitance-coupled multiple field plates, arranged from a plurality of conductive layers, are formed on the insulation layer between the cathode electrode and the anode electrode. The plurality of conductive layers are respectively insulated by the insulation layer and are respectively formed in a floating state (insular state). Also, a rear surface electrode is formed on a rear surface of the semiconductor substrate.